Gas operating system with exhaust system

ABSTRACT

A gas exhaust system for a gas operated firearm may include a rear part connected to a gas block of a gas operating system, and a front part connected to the rear part. The rear part and front part have a flow path defined therealong that allows for venting of gases from the gas operating system. The rear part can have a regulating portion that regulates or control the amount of gases released from the gas operating system.

CROSS REFERENCE TO RELATED APPLICATIONS

The present patent application claims the benefit of the filing date of previously filed, co-pending U.S. Provisional Patent Application Ser. No. 62/423,924, filed Nov. 18, 2016, by the inventors named in the present application.

INCORPORATION BY REFERENCE

The specification and drawings of U.S. Provisional Patent Application No. 62/415,732, filed Nov. 18, 2016, are specifically incorporated herein by reference as if set forth in their entirety.

TECHNICAL FIELD

The present disclosure generally relates to firearms and, more particularly, to gas operated firearms.

BACKGROUND

Semi-Automatic and automatic firearms generally will include gas operating systems that utilize combustion gases from firing to drive the action of the bolt. In some firearms, such as semi-automatic shotguns, the gas system can be configured to accommodate firing of different size cartridges and corresponding loads, e.g., 2¾″ target loads to 3″ Magnum loads. In such firearms, the gas system generally is designed to compensate for cartridges having lighter firing loads to ensure proper operation. As a result, however, when firing cartridges with higher loads, e.g., Magnum cartridges, too much or excess pressurized gases into the gas operating system can be received from the barrel upon firing, which can cause undesirably high bolt velocities during cycling of the action, potentially damaging the bolt or other components of the firearm. Firing of such higher load cartridges also may generate additional recoil forces, as well as enhanced muzzle climb upon firing. To reduce excess pressures, some gas operating systems have compensation plugs that can include a spring-loaded plunger assembly to try to reduce excess pressure in the gas operating system caused by firing of such cartridges having higher loads. These plugs may vent or release the high pressure gases from the gas operating system, for example, into a cavity or chamber defined within or along the fore-end of the firearm. In some firearms, such as firearms that include ornate or custom crafted fore-ends made from lighter and/or decorative materials such as wood, these components can be damaged by the release of such high pressure gases therein, potentially causing injury. Accordingly, it can be seen that a need exists for a gas operating system which addresses the foregoing and other related and unrelated problems in the art.

SUMMARY

Briefly described, the present disclosure is directed to a gas compensating system for a gas operated firearm, which includes an exhaust system or component. The exhaust system may include a kit or an assembly having a series of exhaust tubes that can be coupled to the firearm gas operating system, and which are formed as substantially unitary structures or can include parts or components that can be selectively mounted and/or interchanged with the gas operating system to enable tuning or adjustment of the exhaust system, for example to correspondingly adjust for differing gas pressures as needed for firing different cartridges having different loads. The exhaust tubes of the exhaust system each can include a rear portion that detachably connects or couples to a gas block and a front portion that can be integrally formed with, or fixed to, or can be detachably connected to the rear portion. The rear portion also will include a body with a bore or passage defined therethrough and which at least partially defines a flow path in communication with the gas operating system, to allow for release or diversion of excess gases therefrom. The front portion of the exhaust system can include a generally tubular body with a bore or passage defined therethrough, the bore having an inlet at least partially aligned with the bore of the rear portion so as to be substantially in fluid communication therewith. The tubular body of the front portion further can have one or more outlets or exhaust vents for directing the release or exhaustion of excess pressured gases received from the gas operating system into the ambient environment. Such outlets or vents further can be arranged along an exterior surface of the fore-end portion of the firearm to generally direct the excess gases in a direction so as to help mitigate or affect muzzle climb and/or felt recoil upon firing.

The rear portion of each tube further can include a regulating portion or section configured to regulate or otherwise control the amount of gases entering the upstream end of the bore of the rear portion and thus helps control the amount of gases released from the gas operating system through the exhaust system. In one aspect, the regulating portion can include an inlet orifice and/or chamber arranged along or at the front or distal end of the bore of the rear portion that is sized, dimensioned, or otherwise configured to regulate, control or limit the amount of gases allowed to enter the bore of the rear portion from the gas operating system. The exhaust system thus can include a plurality of exhaust tubes or bodies each having regulating portions with differently sized, dimensioned, or configured orifices designed to divert or vent selected amounts of excess gases from the gas operating system, for example, to substantially correspond to specific cartridges or ranges of cartridges firing different firing loads. Alternatively, the size of the inlet orifice can be adjusted or changed by a regulating mechanism to increase or decrease the size of the orifice, to accommodate for firing of various cartridges having different ranges of firing loads.

In another aspect, the regulating portion may include one or more valve assemblies arranged at least partially along or within the bore of the rear portion to further help regulate gas flows into the exhaust system. For example, the valve assemblies can include a valve member biased by a spring or other biasing element toward a position to at least partially obstruct or block the outlet of the bore of the rear portion, to at least partially seal or restrict the flow of gases therethrough; and when the gas pressure in the gas operating system exceeds to a level sufficient to overcome the biasing force of the spring, the valve member can be moved/urged in a direction away from the bore outlet, to allow release of excess gases from the gas operating system into the exhaust system. Such valve assemblies also can be configured to facilitate firing of cartridges having different firing loads. For example, the stiffness of the spring or biasing member can be varied or adjusted to compensate for cartridges firing different loads or ranges thereof.

The exhaust vents or outlets of the exhaust system further can include guide channels defined along the fore-end portion of the firearm, each with an inlet arranged/aligned substantially adjacent and in communication with the outlet of the bore of the front portion, and an outlet or exit opening defined along an exterior surface of the body of the fore-end of the firearm. Each guide channel further may be configured so as to drive an angled or curved vent/exhaust path to vent the gases exhausted from the gas operating system in a direction and in a manner so as to potentially reduce recoil felt upon firing of the firearm, as well as help reduce muzzle climb of the firearm. For example, the outlets or vents of the exhaust passages may be arranged to vent the excess gases upwardly and outwardly at an angle, away from a top or upper surface of the fore-end of the firearm, and with a force that urges the front end of the firearm downwardly to help reduce muzzle climb.

Various objects, features and advantages of the present invention will become apparent to those skilled in the art upon a review of the following detail description, when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a firearm, e.g., a shotgun, according one aspect of this disclosure.

FIGS. 2A-2B show a gas exhaust system according to principles of this disclosure.

FIG. 3 shows front and rear parts of a gas exhaust system according one aspect of this disclosure.

FIG. 4 shows front and rear parts of a gas exhaust system according to another aspect of this disclosure.

FIG. 5 shows front and rear parts of a gas exhaust system according to yet another aspect of this disclosure.

FIGS. 6A-B shows perspective, partial cutaway view of a flow path arranged along a fore-end of a firearm according to principles of this disclosure.

FIG. 7 illustrates a top view of the firearm showing vents or outlets of the flow path of FIGS. 6A-B.

Those skilled in the art will appreciate and understand that, according to common practice, the various features of the drawings discussed below are not necessarily drawn to scale, and that the dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present invention described herein.

DETAILED DESCRIPTION

Referring now to the drawings in which like numerals indicate like parts throughout the several views, FIGS. 1-7 generally illustrate a gas operating system 10 with an exhaust system 5 according to principles of this disclosure for use in a firearm, such as an auto-loading shotgun (FIG. 1) capable of firing cartridges A having various loads, or other similar type of gas operated firearm. It will be understood, however, that the principles of the gas operating system of the present disclosure can be used in various types of firearms including rifles and other long guns, handguns, and other gas-operated firearms such as M4, M16, AR-15, ACR firearms and the like.

FIGS. 1 and 2A-B show an example of a gas operated firearm F incorporating a gas operating system 10 according to principles of the present disclosure. The firearm F generally includes a barrel 12 having a cartridge firing chamber 13 substantially adjacent or substantially proximate a rear or proximal end 12 a of the barrel 12. The barrel 12 can be mounted to a forward or distal end 14 b of a receiver 14 of the firearm F, and the chamber 13 of the barrel 12 will be in communication with the gas operating system 10, such as through ports 20 (FIGS. 2A-2B). The firearm F further generally will have a bolt 16 that is translatable along the receiver 14 in response to actuation of the gas operating system 10, to cause the bolt 16 to move rearwardly along the receiver 14 for ejecting a spent shell casing from the firearm F. Thereafter, the bolt 16 can move forwardly along the receiver 14 for loading a new cartridge from a magazine 18 into the chamber. In one embodiment, as shown in FIG. 1, the magazine 18 can include a tubular magazine having an opening for receiving and storing rounds of ammunition or cartridges A therein. However, other types of magazines, with different constructions, such as a box style magazine, also can be used without departing from this disclosure.

The firearm F further can have a fore-end part or portion 19 that generally is arranged along the magazine tube and/or adjacent the barrel 12, as shown in FIG. 1. The fore-end 19 will have an elongated body 21 with one or more cavities 23 defined therein, one of which at least partially receives the magazine 18 and the gas operating system and exhaust system, e.g., as shown in FIGS. 2A-2B. In accordance with principles of the present disclosure, the body 21 of the fore-end 19 (FIG. 1) can be formed from substantially lighter-weight and/or more decorative materials, such as wood, without requiring use of substantially high-strength materials, though other materials are possible, such as laminates, synthetics, composites or other suitable materials without departing from this disclosure.

An example of a gas operating system 10 for use with the exhaust system 5 is shown in FIGS. 2A-B and 6B. This gas operating system 10 is actuated, driven or otherwise operable in response to combustion gases from firing the cartridge that can be supplied to the gas operating system 10 from a plurality of transmission ports 20 formed in the barrel 12, and which can be at least partially in fluid communication with one or more gas transmission ports 22 of the gas operating system 10. Although FIGS. 2B and 6B show two corresponding transmission ports 20/22, the barrel 12 and gas operating system 10 can have any arrangement, configuration, or number of gas transmission ports, without departing from this disclosure. The gas transmission ports 20/22 enable gases generated during firing to be tapped or diverted from the chamber 13 and directed into the gas operating system 10 to cycle the firearm F. The plurality of gas transmission ports 20/22 additionally can enable cartridge loads of different “strength” to be fired from the firearm. For example, the plurality of gas transmission ports 20 located along the barrel can be arranged, sized, or configured such that cartridge casings of different lengths can affect the number of active gas transmission ports 20 in the barrel 12, i.e., by covering or leaving certain parts uncovered. Such a configuration of gas transmission ports is described in U.S. Pat. No. 8,065,949, the disclosure of which is hereby incorporated by reference as if presented herein in its entirety.

As also generally shown in FIGS. 2A-B and 6B, in one embodiment, the gas operating system 10 can include a gas cylinder or gas block 24, which can be formed with a concave or otherwise configured upper surface 26, and one or more compensating gas pistons 28. The underside 30 of the firearm barrel may at least partially rest on the upper surface 26 of the gas block 24, with the gas block 24 being mounted, braised or otherwise attached to the underside 30 of the barrel 12 in a manner so that at least some of the gas transmission ports 20/22 are aligned in fluid communication. The gas block 24 also can include one or more longitudinal piston bores 36 each receiving a movable gas piston 28 therealong. The gas pistons 28 will be at least partially received and movable through an opening 40 at a rear or proximal end 36 a of their respective piston bores 36, and can be biased in a forward direction D1 towards a forward or distal end 36 b of their piston bores 36, such as by, e.g., a spring or other suitable biasing mechanism. The pistons 28 will be in operative communication with the bolt 16 of the firearm so that the bolt 16 is driven/actuated in a rearward direction D2 as the compensating gas pistons are moved in the rearward direction D2 by the pressurized gases from firing of a cartridge entering the piston bores 36 through the gas transmission ports 20/22. Other example gas operating systems are described in U.S. Pat. No. 9,097,475 and U.S. Pat. No. 9,383,149, the disclosures of which patents are hereby incorporated by reference as if presented herein in their entirety.

As further shown in FIGS. 2A-B, 3-5, and 6A-7, the gas operating system 10 will include an exhaust system 5 for releasing excess gas pressure from the gas operating system 10. Excess pressure may include any amount of pressure that exceeds a pre-selected or minimum amount of gas pressure for fully cycling the bolt 16 after firing. The exhaust system 5 can render the firearm F capable of firing a range of cartridges, with various shot loads (i.e., 2¾″ target loads to 3″ Magnum loads), by passively or automatically compensating for the excess pressure added to the gas operating system 10 from the firing of cartridges having different shot loads. For example, the gas operating system 10 will vent or otherwise release excess gases from the gas exhaust system 5 to reduce or otherwise control the magnitude of the gas pressure driving the compensating gas pistons, to thus regulate or control the velocity of the bolt 16 during cycling thereof by the pistons 28. This may prevent damage to, or otherwise increase the service life of, the bolt 16 or other components of the firearm F, when cartridges having various/different shots loads are fired therefrom. The exhaust system 5 will be in communication with the longitudinal piston bores 36 and will redirect excess gases from the piston bores 36 for release or venting to the ambient atmosphere/environment.

For example, as generally shown in FIGS. 6A-B, the exhaust system 5 generally will include one or more exhaust tubes or conduits 62, each defining a flow path or passageway 42 that is in communication with an opening 44 at the front or distal end 36 b of a respective one of the piston bores 36. The exhaust tubes can be formed as substantially unitary structures or can include interchangeable parts or components for ease of cleaning and/or tuning of the gas system to accommodate for different firing loads or conditions. The exhaust tubes also can have one or more outlets or exhaust vents 46 arranged along an outer or exterior surface 48 of the body 21 of the fore-end 19 to release excess gases outside of the body 21 of the fore-end 19. Each flow path 42 also can include a redirecting portion or guide channel 50 configured to re-direct or otherwise control the exiting flow of the gases along the flow path 42, for example, upwardly and outwardly at an angle to help reduce recoil forces and/or substantially reduce muzzle climb experienced upon firing. Each exhaust tube also will have a restricting or regulating portion or section 52 at an upstream end of the flow path 42 to control or limit the amount of gases received from the gas operating system 5 (FIGS. 2B and 3-5). This regulating portion 52 also may be adjustable or tunable to vary the amount of gases released from the gas operating system 5, i.e., to provide sufficient pressure to ensure full cycling of the bolt for cartridges having the lightest loads, while regulating and limiting dispersion of excess gases through the fore-end 19.

As indicated in FIGS. 2A-5, the gas compensating exhaust system 5 can comprise a kit or assembly 60 having or provided with a series of exhaust tubes 62 and/or other components that can be selectively interchanged or substituted to enable the exhaust system 5 to be adjusted or tuned to correspond to firing of specific cartridges or ranges of cartridges having different, varying shot loads. The exhaust assembly or kit 60 further can be provided with a plurality of parts or components including a series of different interchangeable exhaust tubes, and/or interchangeable rear and front portions 64/68, each having a regulating portion 52 that can be configured to be used with specific cartridge loads or ranges thereof to enable easy replacement or change-out of the exhaust system components as needed to facilitate firing of cartridges having different loads. For example, if a shooter/user is using the firearm for target shooting, and thus shooting lower pressure target loads, exhaust tubes having a reduced or more restricted regulating portion can be used to ensure proper cycling of the bolt with exhaustion of excess gases needed generally only for isolated pressure spikes. When the shooter is using higher pressure, heavier loads, such as heavy 2¾″ shells, the exhaust tubes, or components thereof, can be easily swapped or changed to provide for larger volumes of excess pressurized gases to be exhausted or vented, without having to replace or reconfigure the entire gas operating system of the firearm.

As shown in FIGS. 2A-2B, each of the exhaust tubes 62 will have a rear or proximal portion or part 64 that can be removably coupled or otherwise connected to the gas block 24 such that a fluid passage or pathway 66 defined therealong is at least partially in communication with at least one of the piston bores 36 of the gas block 24 to allow for release or venting of gases therefrom. A forward or distal portion or part 68 extends from the rear portion 64 of each exhaust tube and has a fluid passage or pathway 70 defined therealong that is in communication with the passage 66 of the rear portion 64, and which fluid passage 70 terminates at an outlet or vent 72 for release of gases therefrom. The forward portion 68 of each exhaust tube can be fixed to, or can be integrally formed with, the rear portion 64 (FIGS. 2A-B); or, alternatively, the forward portion 68 can be detachably mated or otherwise removably connected to its rear portion 64 (FIGS. 4-5). The regulating portion 52 of the exhaust system 5 generally will be arranged along the rear portion 64 of each exhaust tube, in a location to help control or regulate the amount of gases that enter the fluid passage 56 of the exhaust system.

FIGS. 2A-5 further show the rear portion 64 including an elongated body 74 that can be formed with a generally cylindrical shape, though other shapes are possible without departing from this disclosure. As generally shown in FIG. 2B, a front or proximal end 74 a of the body 74 may be at least partially received within the opening 44 at the front or distal end 36 b of an associated piston bore 36, for example, by engagement of threads 78 arranged along an exterior surface 80 of the body 74 with a corresponding series of threads 82 arranged along an interior surface 84 of the piston bore 36. Any other suitable connections, such as a pinned connector or other disengageable coupling also can be used without departing from this disclosure. The body 74 further can include an annular recess 84 defining a seat for receiving an O-ring 86, or other sealing feature, to substantially seal the connection between the piston bore 36 and the rear portion 64 of the exhaust tube 62 (FIGS. 3 and 5). The body 74 of each rear portion further can include a shoulder 88 arranged/positioned along its exterior surface 80 that engages or bears against the forward portion 90 of the gas block 24 as the rear portion 64 is engaged within the piston bore 36, to help prevent over insertion of the rear portion 64 into the piston bore 36. The body 74 also can have a portion or section 92 that is shaped or configured to facilitate connection and removal of the rear portion 64 to the gas block 24. For example, as shown in FIGS. 2A and 3, portion 92 can have flat portions or a hexagonal shape to facilitate attachment or removal of the rear portion 64 to the gas block 24, such as by a wrench or other suitable tool; although this portion 92 can have any suitable shape, such as another polygonal or square shape, without departing from this disclosure.

In addition, the rear portion 64 of each exhaust tube will have a bore or inlet 94 defined therethrough, and which at least partially defines a first portion of the exhaust/fluid passageway 66 and the regulating portion 52 of the exhaust tube, as generally shown in FIGS. 2B and 4-5. This bore 94 will have a central axis 95 that generally will be substantially parallel to the longitudinal axis of the firearm F. In one aspect, the bore 94 will have an upstream or inlet opening or orifice 96 at a first proximal end 94 a, and will be sized, dimensioned, or otherwise configured to regulate, limit or control the amount of excess pressurized gases allowed to enter the bore 94/passage 66 from the piston bore 36 of the gas operating system (FIGS. 2B and 4). The size, dimensions, or configuration of this bore 94/orifice 96 can be varied or selected to correspond to a specific cartridge or range of firing loads. For example, the exhaust kit or assembly 60 can be provided with one or more exhaust tubes 62 and/or rear portions 64 thereof, each having a smaller orifice for use when firing cartridges with lighter/smaller loads to ensure sufficient gas pressure remains within the piston bore 36 to fully cycle the bolt 16 upon firing, and/or further can include one or more exhaust tubes and/or rear portions thereof with larger orifices for use when firing cartridges with higher loads, so as to bleed off excess gases as needed to limit/maintain the bolt 16 velocity and prevent damage to the bolt 16 or other components of the firearm F. Alternatively, an adjustment mechanism enabling a user to adjust or vary the size or dimensions of the orifice 96 also can be provided for selectively tuning the orifice to correspond to specific cartridges having different loads.

As illustrated in FIG. 4, the inlet bore 94 will open into the fluid/exhaust passageway 66 at the upstream end thereof, and generally will be of a smaller dimension or size than the fluid passageway 66. As a result, an expansion of the pressurized gases passing through the bore 94 and into the fluid passageway 66 is provided, which helps reduce the pressure of these gases. The pressurized gases thereafter continue to expand and flow along the front portion 68 of each exhaust tube 62 to a selected exhaust or venting position defined along the fore-end of the firearm. For example, the gases can be vented away, i.e., upwardly and/or outwardly, from the fore-end, or through openings formed along or adjacent the body 21 of the fore-end 19, or the magazine plug 17, in a direction that helps to substantially reduce the pressure of gases impacting on the fore-end 19 and which can help provide additional, counter acting forces to help reduce muzzle climb and/or felt recoil upon firing.

In another aspect of this disclosure, the regulating portion 52 may include one or more compensating valve assemblies 98 arranged at least partially along, or downstream from, the bore/inlet 94 of each exhaust tube(s) 62, such as shown at (FIG. 5). The valve assemblies 98 can include a movable valve member 100 that is biased by a valve spring 102, or other suitable biasing member, with a forward or proximal end 100 a of the valve member 100 sized, dimensioned or shaped to at least partially obstruct or block the downstream or outlet opening or aperture 104 of the bore 94 to at least partially seal or restrict gases the flow of gases therein. For example, the proximal end 100 a of the valve member 100 can include a frustoconical shape that can be sized and dimensioned to at least partially fit/nest within or frictionally engage the outlet opening of the bore 104 as indicated, though the proximal end 100 a can include any suitable shape, e.g., a spherical, curved, or arcuate shape, that will at least partially obstruct the flow of gases into the opening 104.

The valve spring 102 will bias the valve member 100 in a rearward direction D2 with a force generally sufficient to at least partially block or restrict the flow of gases through the opening 104, until excess gas pressure in the piston bore 36/bore 94 rises to a level sufficient to overcome the spring force of the valve spring 84. Thereafter, the gases will urge the valve member 100 in a forward direction D1 away from its biased, selected engagement over the opening 104 to allow passage of the gases therethrough and into the passageway 70 of the front portion 68 of the exhaust tube. The valve assembly 98 further can be configured for firing of a desired range of firing loads. For example, the valve spring can be selected to provide a biasing force sufficient to block escape of gases through the exhaust system, when firing cartridges with lower pressure (i.e., target) loads, while requiring higher pressures, such as resulting from firing of heavier loads, such as Magnum loads, to release gases into the exhaust system 5. Also, a series of springs, or other biasing mechanisms, with differing stiffness can be interchangeably used with the valve assembly, or the valve assembly can include a mechanism to adjust the stiffness of the spring, e.g. tighten or loosen the relative stiffness of the spring, to tune the valve to correspond to specific cartridges having different firing loads.

As shown in FIGS. 2B and 4, the front portion 68 of each exhaust tube 62 will include an elongated body 106, typically having a substantially cylindrical or tubular shape, though other shapes are possible without departing from this disclosure. The tubular body 106 of the front portion 68 further can have a bore or channel 108 defined therethrough at least partially defining fluid path 70/continuation of passageway 66, with a central axis 109 that extends substantially parallel to the longitudinal axis of the firearm, and substantially aligned with the central axis 95 of the rear portion 64. The bore 108 will have an inlet opening 110 at a first or proximal end 108 a thereof and an outlet 72 defined at a forward, second or distal end 108 b thereof. The inlet 110 will be at least partially aligned with an outlet 114 of the fluid passageway of the rear portion 64, in fluid communication therewith to enable release of gases from the piston bore 36 through the exhaust tube 62 and out of the outlet 72. The tubular body 106 further can be formed with a sufficient length such that the gases are released from the exhaust system at a downstream location that can be adjacent a forward end of the fore-end and/or which is outside of one or more cavities defined along the fore-end of the firearm F, so as to prevent a build-up of excess pressure within the fore-end.

In one aspect of this disclosure, as noted, the tubular body 106 of the front portion 68 can be integrally formed with the body 74 of the rear portion 64 of each exhaust tube 62 (FIG. 2A), as a substantially unitary structure, although the front and rear portions 64/68 also can be formed separately and can be fixed together in any suitable manner, such as by brazing or welding, without departing from this disclosure. In other aspect of this disclosure, the tubular body 106 of the front portion 68 can be detachably coupled or connected to the body 74 of the rear portion 64 (FIGS. 4 and 5), for example, with the tubular body 106 engaging the body 74 of the rear portion 64 using threads 112 arranged along an interior surface 113 of the body 74 of the rear portion 64 that matably engage with threads 114 arranged along an exterior surface 115 of the tubular body 106 of the front portion 78. The tubular body 106 further may have a shoulder 116 arranged along its exterior surface 114 adjacent the end which may engage or bear against the distal end of the body of the rear portion 64 to limit movement/insertion of the tubular body therein. The tubular body 106 also can have a locking portion or section 117 (e.g., a hex nut or flat portions), arranged substantially adjacent the shoulder 116 and shaped or configured to facilitate connection and removal of the front and rear portions 68/64, such as by a wrench or other suitable tool.

In yet another aspect of this disclosure, the tubular body 106 of a forward portion 68 and the body 74 of a rear portion 64 may be connected together by a coupling 118, such as generally shown in FIG. 4. Such a coupling 118 can have a body 120 with a passageway or channel 122 defined therethrough, an opening 124 at a proximal end 122 a sized to at least partially receive the body 74 of a selected rear portion 64, and an opening 126 at its distal end 122 b sized to at least partially receive a tubular body 106 of a selected forward portion 68. The body 120 of the coupling 118 further can have a series of threads 127 arranged along an interior surface 128 thereof and configured to matably engage with corresponding threads 130/132 formed along the exterior surfaces of the tubular body 106 and the body 74 of the rear portion 64, so as to couple or connect the selected front and rear portions 68/64 together.

FIGS. 6A-B and 7 illustrate examples of the venting or exhaustion of gases from the gas exhaust system 5 through the fore-end 119 of the firearm F. In one aspect, the exhaust system 5 can include one or more outlet bore(s)/channel(s) 140, each having an inlet 142 located substantially adjacent and at least partially aligned in communication with the outlet 72 of a tubular body 106 of the front portion 68 of an exhaust tube 62, and an outlet or vent opening 46 defined along an exterior surface 48 of the body 21 of the fore-end portion 19 of the firearm F. The outlet channel(s) 140 further can be configured or arranged to direct or guide the gases released from the gas operating system out of and away from the fore-end in a manner/direction so as to help limit or reduce muzzle climb and/or recoil force experienced upon firing of the firearm F. For example, as shown in FIG. 7A, the channel(s) 140 may have an angled, curved or generally L-shaped configuration with a first or forward portion 150 having a central axis 152 that is substantially parallel to the central axis 109 of the bore of the tubular body 106 in communication therewith, and a redirecting portion 154 having an axis 156 that is at an angle with respect to the central axis 152 of the first portion 150, to thereby alter the direction of the gases released from the gas operating system 10. The redirecting portion(s) 154 thus can cause the gases flowing therealong to pass upwardly and/or outwardly, away from the fore-end, i.e., through vent(s) 46 along the fore-end body 21 at an angle of about 30° to about 45°, though other, greater or lesser exhaust angles also can be provided. The redirection of the exhaust gases helps to minimize impact of the pressurized gases within and/or against the fore-end, protecting fore-ends made from lighter-weight or weaker materials such as wood.

In addition, as shown in FIG. 7, the outlet(s) or vent(s) 46 of the bore(s) in the fore-end 19 of the firearm F further may be positioned or arranged such that gases exhausted therefrom provide a generally downwardly directed force that can act to help resist or limit muzzle climb, such that the amount of muzzle climb experienced upon firing is reduced by at least a non-trivial amount. For example, these outlets or vents 46 may be arranged along a top or upper surface 158 of the body of the fore-end 19 to direct the gases exhausted therefrom in an upward and forwardly angled direction to at least partially direct the firearm in a downward direction to counter-act muzzle climb upon firing. However, the outlet or vent of the bore(s) in the fore-end may be arranged along any surface of the body of the fore-end, such as a front surface, without departing from this disclosure. The exhaustion of the excess pressurized gases in a forward direction also can help provide a counter force to further help reduce felt recoil from firing.

Accordingly, the present disclosure provides a gas operating system for a firearm with an exhaust system that has a reduced number of parts and which can allow for tuning or adjustment of the gas operating system to accommodate different cartridge loads in any easy and efficient manner. For example, the exhaust system can comprise one or more exhaust tubes with regulating portions designed for particular types or ranges of cartridges, which can be interchanged as needed for use with other cartridge types. The exhaust system can be used with existing gas systems, in place of a compensating plug, and further provides for protection of fore-ends made from lighter-weight, decorative, and/or weaker materials such as wood, in an efficient and cost effective manner.

The foregoing description generally illustrates and describes various embodiments of the present disclosure. It will, however, be understood by those skilled in the art that various changes and modifications can be made to the above-discussed construction of without departing from the spirit and scope thereof as disclosed herein, and that it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as being illustrative, and not to be taken in a limiting sense. Furthermore, the scope of the present disclosure shall be construed to cover various modifications, combinations, additions, alterations, etc., above and to the above-described embodiments, which shall be considered to be within the scope of the present disclosure. Accordingly, various features and characteristics of the present disclosure as discussed herein may be selectively interchanged and applied to other illustrated and non-illustrated embodiments, and numerous variations, modifications, and additions further can be made thereto without departing from the spirit and scope of the present invention as set forth in the appended claims. 

What is claimed is:
 1. A firearm, comprising: a receiver; a barrel mounted to the receiver and comprising a chamber located at a proximal end of the barrel and configured to receive cartridges for firing from the firearm; a fore-end extending along the barrel; a bolt assembly translatable along the receiver for loading cartridges into the chamber and ejecting spent casings from the firearm after firing; and a gas operating system driving movement of the bolt assembly along the receiver, the gas operating system comprising: a gas block having a longitudinal piston bore in fluid communication with the barrel for passage of gases generated during firing into the piston bore and comprising an opening at a distal end thereof; a gas piston disposed within and movable along the piston bore, the gas piston operatively connected to the bolt assembly to cause the bolt assembly to be driven along the receiver for cycling the firearm; and an exhaust tube coupled to the distal end of the gas block and defining a fluid passageway that is in communication with the piston bore to allow for release or diversion of excess gases therefrom and in a direction substantially along the fore-end; and a regulating portion at an upstream end of the fluid passageway defined by the exhaust tube and configured to regulate or control an amount of gases entering into the fluid passageway.
 2. The firearm of claim 1, wherein the exhaust tube comprises: a rear portion configured to be detachably coupled to the gas block, and having an inlet of the fluid passageway defined therein the outlet at least partially in communication with the piston bore of the gas block; and a forward portion extending forwardly from the rear portion, and through which the fluid passageway of the exhaust tube extends, wherein the fluid passageway is at least partially in fluid communication with the inlet of the rear portion, and terminates in an outlet that allows for release of gases therefrom.
 3. The firearm of claim 1, wherein the regulating portion comprises an inlet arranged along an upstream end of the fluid passage, and wherein the inlet bore has a reduced size in relation to the fluid passage.
 4. The firearm of claim 1, wherein the regulating portion comprises a valve assembly having a valve member that is biased toward a position at least partially obstructing an opening of the fluid passageway to restrict gas flow into the fluid passageway.
 5. The firearm of claim 1, wherein the fluid passageway of the exhaust tube is in communication with at least one outlet channel defined along the fore-end of the firearm, the outlet channel having at least one vent opening defined along an exterior surface of the fore-end of the firearm.
 6. The firearm of claim 5, wherein the outlet channel comprises a redirecting portion that alters a direction of the flow of gases released from the gas operating system.
 7. The firearm of claim 6, wherein the redirecting portion comprises an angled or slanted portion.
 8. The firearm of claim 5, wherein the opening is defined along an upper portion of the fore-end to provide a generally downwardly directed force to at least partially reduce muzzle climb experienced during firing of the firearm.
 9. The firearm of claim 1, wherein the exhaust tube comprises a body having an exterior surface with one or more threaded portions arranged therealong and configured to matably engage with one or more threaded portions arranged along an interior surface of the gas block for connection of the gas block to the exhaust tube, wherein the exterior surface of the body further comprises an annular recess configured to at least partially receive an O-ring sufficient to substantially seal the connection between the piston bore and the exhaust tube.
 10. An auto-loading shotgun, comprising: a receiver; a barrel mounted to a forward end of the receiver, the barrel comprising at least one gas port arranged therealong, and a chamber located at a proximal end of the barrel and configured to receive cartridges for firing; a magazine configured to store cartridges for loading into the chamber; a fore-end portion having a body that at least partially surrounds the magazine and/or the barrel; a bolt assembly translatable along the receiver for loading cartridges from the magazine into the chamber and for ejecting spent casings from the shotgun after firing; and a gas operating system for driving movement of the bolt assembly along the receiver, the gas operating system comprising: a gas cylinder having a longitudinal piston bore, and one or more ports in fluid communication with the piston bore and the at least one gas port of the barrel for directing passage of pressurized gases generated during firing from the barrel to the piston bore; a gas piston disposed within and movable along the piston bore, the gas piston operatively connected to the bolt assembly such that the pressurized gases passing into the piston bore and drive the gas piston therealong so as to cause the bolt assembly to translate along the receiver for cycling the shotgun; and at least one exhaust tube in communication with the piston bore of the gas cylinder, the at least one exhaust tube defining a fluid passageway at least partially in communication with the piston bore and at least one outlet that is in communication with one or more vents defined along an exterior surface of the body of the fore-end portion.
 11. The shotgun of claim 10, further comprising a regulating portion located along the fluid passageway of the exhaust tube, and configured to regulate or control a flow of gases entering the fluid passageway of the exhaust tube.
 12. The shotgun of claim 11, wherein the regulating portion comprises an inlet bore extending along the upstream end of the fluid passageway, and wherein the inlet bore has a reduced size in relation to the fluid passageway.
 13. The shotgun of claim 11, wherein the regulating portion comprises a valve assembly having a valve member biased in a direction to at least partially obstruct an opening of the fluid passageway sufficient to restrict gas flow into the fluid passageway.
 14. The shotgun of claim 10, wherein the exhaust tube comprises: a rear portion configured to detachably couple to the gas block and defining a fluid passageway therethrough that communicates with the piston bore of the gas block; and a forward portion extending forwardly from the rear portion, and through which a fluid passageway extends; and wherein the fluid passageway extends from the rear portion through the forward portion, and terminates at the outlet to facilitate release of gases through the one or more vents.
 15. The shotgun of claim 10, wherein the body of the fore-end portion comprises an outlet channel in communication with the at least one outlet of the fluid passageway of the exhaust tube, and wherein the outlet channel comprises a redirecting portion that alters the direction of the flow of gases passing through the outlet channel.
 16. The shotgun of claim 15, wherein the one or more vents of the body of the fore-end portion are defined along an upper surface of the fore-end portion and are arranged to provide a generally downwardly directed force to at least partially reduce muzzle climb experienced during firing of the shotgun.
 17. The shotgun of claim 10, wherein the fore-end portion is formed from wood, laminates, synthetics, composite materials, or combinations thereof.
 18. A kit for a firearm to facilitate firing rounds of different or varying shot loads, the kit comprising: a series of exhaust tubes configured to be selectively interchanged or substituted to enable adjustment or tuning of the firearm for firing of specific cartridges or ranges of cartridges having different or varying shot loads; each exhaust tube of the series of exhaust tubes comprising: a body having a fluid passageway defined therethrough; a rear portion having a first portion of the fluid passageway defined therein, and configured to be coupled to a gas block of the firearm such that the fluid passageway of the rear portion is in communication with a longitudinal piston bore of the gas block; a front portion coupled to the rear portion and comprising a second portion or combination of fluid passageway in the fluid passageway of the rear portion, and an outlet to facilitate release of gases from the gas block generated from firing the firearm; and a regulating portion disposed along an upstream end of the first portion of fluid passageway, that extends through the rear portion of the exhaust tube, the regulating portion configured to be used with selected cartridge loads or ranges thereof to enable replacement or change-out of the exhaust system components as needed to facilitate firing of cartridges having different loads. 